In many situations, computers are connected to peripherals or electronic appliances using wire connections. One type of wire connection is the Universal Serial Bus (hereafter USB) cable. A USB cable may be used to electrically connect a computer with peripherals and other electronic appliances. Examples of computer peripherals are input devices such as a mouse and a keyboard, output devices such as printers, and input/output devices such as external hard drives and flash memory drives. Examples of electronic appliances are digital cameras, PDAs, and MP3 players.
In the late 1990's the USB standard became the preferred connection interface in the computer industry and has become ubiquitous in almost all computers manufactured today. Laptop computers, desktop computers, and other computing machines are manufactured with USB ports in order to take advantage of the variety of peripheral devices and electronic appliances that are built around USB architecture. (See www.USB.org)
The Universal Serial Bus and USB connectors are well known in the art. The pervasiveness of the USB standard and USB connectors has increased utility to consumers, substantially increased data transfer rates over other interface methods and reduced costs for manufacturers of peripheral devices due to standardization. Computer vendors typically incorporate one or more USB ports into their suite of Input Output ports.
A USB cable used to connect peripherals or electronic appliances to a computer is comprised of 2 endpoints known as connectors or plugs. One connector, known as Series “A” plug, is attached to the host computer and the other, known as Series “B” plug, is attached to the connecting appliance. Series “A” and Series “B” plugs are of different shape and size so as not to confuse between them. The interface connection on the host computer is called USB mount port (hereafter USB port). The USB port is comprised of a Series “A” receptacle that mates with a Series “A” plug. Electrically, Series “A” receptacles function as outputs from host systems. FIG. 1 shows a prior art Series “A” plug 10, which mates with a Series “A” receptacle 12. The Series “A” plug always is oriented towards the host system. Photographs of the plug and connector are shown in the provisional application Ser. No. 60/490,413, filed Jul. 28, 2003, entitled “Electrical Connector” (hereinafter “the provisional application”) which is incorporated herein by reference.
The computer host USB port is an open receptacle with a flat, internal rectangular card bearing electrical contact points. The cable series “A” plug connecting to the host receptacle terminates in a rectangular sleeve that is inserted into the host receptacle. The sleeve contains a tongue board bearing matching electrical contact points to those of the host receptacle. The insertion of sleeve to the receptacle affixes the card and tongue thus creating a mated electrical connection.
Some peripheral devices do not employ a USB cable to connect to a computer but rather utilize a USB connector as part of their assembly. Examples are keychain storage devices (see www.diskonkey.com, www.thumbdrive.com) or security keys (see www.ealaddin.com). The provisional application shows an example of a USB drive plugged into a host PC USB port. Keychain storage devices, due to their small dimensions, serve as portable storage media, and as such are often used with several computers. Therefore, these devices are plugged in and out of host computers many times.
There is unfortunately a shortcoming in the physical design of the USB connector, which manifests itself when a attempting to insert a USB connector into a USB port. Referring again to FIG. 1, it can be seen that while seeming symmetric to touch and sight externally, both the receptacle 12 and the plug 10 are asymmetric internally. In the host receptacle, this is due to the positioning of the rectangular card 101 and electrical connectors 102 inside the receptacle. FIGS. 2a-2c show an example of a USB host receptacle 100. FIG. 2 depicts three views of a USB receptacle of the prior art. In particular, FIG. 2a shows a front section, FIG. 2b shows a side view section, and FIG. 2c shows a bottom side view section. Referring to these figures, a rectangular card 101 is located within the receptacle 100. Electric contact points 102 are formed on the card 101.
FIGS. 3a-3c depict an example of a Series “A” USB plug of the prior art. In particular, FIG. 3a depicts a top view section, FIG. 3b depicts a front view section, and FIG. 3c depicts a side view section. The prior art plug connector includes a shell 200. A tongue board 201 is located within the shell and electric contact points 202 are formed on the tongue board. Similarly, inside the USB connector shell 200, the tongue 201 and electrical contacts 202 are positioned in a non-symmetric manner.
In many cases, the host USB port is located at an angle in which users can't comfortably see the inside of the receptacle, and it is unclear to the user how to align the plug for proper insertion and electrical mating. FIGS. 4 and 5 depict mating a USB plug and a USB receptacle of the prior art. The rectangular sleeve of a USB plug fits correctly into the rectangular receptacle 100 of the USB port only when the internal rectangular card 101 of the receptacle and the internal tongue board 201 of the USB plug are correctly facing each other as shown in FIG. 4. FIG. 5 illustrates the case when the plug is correctly inserted into the receptacle. When this is not the case, an electric mating is not possible as the internal rectangular card 101 of the receptacle and the internal tongue board 201 of the USB connector collide as shown in FIGS. 6a and 6b, also prior art. FIG. 6a shows a view similar to that of FIG. 5 except that the receptacle 100 and shell 200 are not properly aligned. FIG. 6b shows the collision 205 that results from this misalignment.
In some cases, users may not see the internal alignment in the host USB receptacle because it is positioned in the back or on the side of the computer. Statistically, since there are seemingly two alignment possibilities when connecting the rectangular plug to the rectangular receptacle, but only one correct alignment, there is a 50% chance of failed insertion attempts. The result is a degradation of the user experience in working with USB devices. As more devices connect to computers using USB connectors, this problem intensifies. For keychain storage devices that are plugged many times in and out of many computers, this inconvenience intensifies.
There is clearly an unmet need for a plug mechanism that is operable with the USB that allows correct insertion of the plug into a USB port without necessitating user consideration of plug alignment.